| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave filter which improves the balancing between balance signal terminals 11 and 12, and a communication device using it. SOLUTION: Three interdigital electrodes 5, 4, and 6 are provided to have balance-unbalance conversion functions. Balance signal terminals 11 and 12 are connected to the interdigital electrode 4. The electrode fingers at both ends, which are connected to the balance signal terminal 11, in the interdigital electrode 4, are divided into two electrodes fingers 15a and 15b. The electrode fingers 15b are connected to ground via adjacent interdigital electrodes 5 and 6.
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